Verification of a dimensionless parameter model for laser beam welding
- Sandia National Lab., Albuquerque, NM (United States)
In recent years, fusion welding processes have become more automated as computers are increasingly installed to improve product quality by more precise control of the manufacturing process. Two important `figures of merit` to help characterize automated fusion welding processes are the energy transfer efficiency and the melting efficiency. During weld schedule development, a knowledge of these efficiencies can be used to optimize the process and improve weld quality. Recent calorimetric based studies of the CO{sub 2} laser beam welding process at Sandia have demonstrated a good correlation between these efficiencies and certain little known dimensionless parameters originally given by Rykalin and Christensen for arc welding processes. A simple mathematical relationship between these parameters has been found and can be used to quickly estimate the heat input to the part based on the size of the weld or for other optimization tasks such as selecting the required travel speed to maximize the melting efficiency. These dimensionless parameters have been shown to correctly account for the large differences in melting that occur when welding metals with room temperature thermophysical properties as dissimilar as 1018 steel and stainless steel. Continuous wave CO{sub 2} laser beam welds were made on 12.7 mm thick pure tin specimen plates mounted in a Seebeck envelope calorimeter. Because of the difficulty in obtaining scratch-free surfaces, the tin specimens were lapped to a 32 {mu}in. finish. Laser power, focused spot diameter, and travel speed were varied in a matrix of conditions which resulted in a wide range of variation for the dimensionless parameters. The resulting welds were cross-sectioned and the weld volume determined; when combined with the net heat input to the part, the velocity, and the thermophysical properties at the melting point, the dimensionless parameters were determined exactly.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 115431
- Report Number(s):
- CONF-9404233--
- Country of Publication:
- United States
- Language:
- English
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